Casita builder in Oro Valley, AZ

Oro Valley writes its own casita rules

Arizona's 2024 ADU law, HB 2720, only binds cities with more than 75,000 people. Oro Valley is smaller than that, so the state's casita rules that apply in Tucson do not automatically apply here. Instead, the town updated its own zoning code. The Town Council adopted Ordinance (O)24-12 on December 4, 2024, and it took effect on January 3, 2025. It added a definition of an accessory dwelling unit and new ADU standards for the single-family zoning districts.

What the town's ADU standards say

Based on the town's published code amendments, the main points for a casita on a single-family lot are:

• One ADU per lot. It can be attached to the house or detached.
• Size. The ADU can't be larger than the main house on the lot.
• Setbacks. The front setback is the same as for the house. Side and rear setbacks are 5 feet, with 5 feet between buildings.
• Height. The same height limit as a single-family home in that zone.
• Parking. No additional parking can be required.
• Driveway. An ADU sitting between the house and the street can't have its own attached garage, carport or street driveway, and must share the main driveway. A separate driveway is only allowed for an ADU in the side or rear yard.
• Design. The town's exterior design, roof pitch and finish material standards don't apply to the ADU itself.

The code also separates a guest house from an ADU. A guest house is an accessory building for guests of the people living in the main house, and once it has a kitchen the town treats it as a dwelling unit. That distinction affects how your plans are reviewed, so we settle it before drawings start.

Your HOA usually has the final say on looks

The town may not regulate an ADU's exterior style, but most Oro Valley neighborhoods have CC&Rs that do. Rancho Vistoso, for example, is a planned area development with its own design guidelines and an architectural review committee. Expect the HOA to look at height, stucco color, roof material and where the casita sits. We prepare the plans, materials and colors your committee asks for, and we plan HOA review ahead of the town permit. See our Rancho Vistoso contractor page for more on that community.

Lot details we check in Oro Valley

• Washes and sensitive land. Oro Valley's Environmentally Sensitive Lands rules protect riparian areas, hillsides and the scenic corridors along Oracle and Tangerine Roads. Which parts apply depends on your lot's zoning and location.
• Grading and soils. The town's residential construction handbook notes that new buildings and additions may need a grading permit, and lots that weren't mass graded need a soils report with foundation recommendations. Caliche is common, so we want to know early.
• Sewer or septic. The handbook also asks for proof that the Pima County sewer or septic fee has been paid before the permit is issued.
• Matching the house. Even where the town doesn't require it, a casita that matches the home's stucco and roof looks original and keeps the HOA happy.

Attached suite or detached casita?

Oro Valley's ADU standards cover both. An attached unit shares a wall and roof with the house, is often simpler for plumbing and power, and suits a parent who wants to be close. A detached casita gives more privacy for long visits or adult children, but needs its own foundation, roof and utility runs from the house. On lots where the yard is tight against the 5 foot side and rear setbacks, attached is sometimes the only shape that works. Our casita vs home addition guide goes through the trade-offs in more detail.

How we build a casita in Oro Valley

1. Site walk. We look at the lot, confirm it is inside town limits, and talk through size, layout, utilities and budget.
2. Jurisdiction and HOA check. We review the town's ADU standards for your zone and your HOA's guidelines together.
3. Plans. Custom drawings or an adapted plan, plus the site plan, grading and soils items the town needs. Our casita floor plan guide is a good starting point.
4. Permits. HOA submittal, then the town permit. We answer review comments.
5. Build. Foundation, then framing, structural work, roofing and stucco by our own crew, then interiors.
6. Inspections and walk-through. We schedule inspections and walk the finished casita with you.

For ballpark numbers, read our casita cost guide. For how rules differ across the metro, see building a casita in Tucson. For all our Oro Valley work, visit the Oro Valley contractor page.